Written By: Khawja Labib

Introduction

As of 2023, humanity has made significant progress towards achieving sustainable energy solutions. However, as we live in an age of great innovation, humans have turned to space to produce renewable energy. Receiving energy directly from the sun is one of the most intuitive ideas. By directly, I mean right beside the Sun. "Well, we already have solar panels on Earth!" you may be thinking. I'll try to persuade you of the benefits of having solar panels directly facing the Sun while also pointing out some drawbacks.

Problems of Solar Panels on Earth

There are two major issues with the use of solar panels on Earth. To begin with, sunlight is only available from sunrise to sunset, so no energy is produced for half of the day. Second, on cloudy days, the solar panels receive no sunlight at all, which is problematic in countries such as England, where the weather is frequently overcast. Installing solar panels in space solved these issues because sunlight is available 24 hours a day, 365 days a year.

The Design

“ESA - Space-Based Solar Power overview.” Accessed: Nov. 14, 2023. [Online]. Available: https://www.esa.int/Enabling_Support/Space_Engineering_Technology/SOLARIS/Space-Based_Solar_Power_overview

The diagram above is based on a design provided by the European Space Agency. Photovoltaic cells convert solar energy into electricity, it is then transmitted to Earth in the form of 2.45 GHz microwaves [1]. The receiver then converts the signal to usable energy, which is then distributed to power grids [1]. This idea may appear to be too difficult to implement, but it has been researched for a long time. In fact, in 2023, Caltech's "Space Solar Power Demonstrator" was able to wirelessly transmit power from space to Earth [2]. The SSPD-1 experiment that accomplished this feat is known as the MAPLE, which stands for "Microwave Array for Power-transfer Low-orbit Experiment" [2]. This device is composed of lightweight power transmitters that direct energy to the intended location [2]. These devices must be lightweight in order for transportation to be affordable and feasible [2]. This project was led by Bren Professor of Electrical Engineering and Medical Engineering and co-director of SSPP with the Caltech team [2].

Disadvantages

With the obvious benefits comes a major issue: cost. To get the transmitters into space, they must be launched in rockets, which are extremely expensive. In addition, the costs associated with failed launches must be considered. Another disadvantage is that this arrangement necessitates the construction of large structures both in space and on Earth [1]. Repairing these massive structures would be equally difficult [3]. To summarize, the problems are primarily cost and feasibility concerns. On the bright side, according to The European Space Agency, launch costs are falling, so the design can still be realized [1].

Conclusion

In conclusion, the quest for space-based solar power signals a transformative leap in sustainable energy. Overcoming the limitations of Earth-based panels, innovations like Caltech's "Space Solar Power Demonstrator" offer a glimpse into a future where energy is harnessed directly from the sun in space and beamed to Earth. While challenges such as launch costs and infrastructure maintenance persist, the decreasing cost of space launches and ongoing research provide optimism. The journey toward space-based solar power is complex, but its potential to revolutionize our energy landscape is undeniably compelling, pointing towards a brighter and more sustainable future.

References

[1] “ESA - Space-Based Solar Power overview.” Accessed: Nov. 14, 2023. [Online]. Available: https://www.esa.int/Enabling_Support/Space_Engineering_Technology/SOLARIS/Space-Based_Solar_Power_overview

[2] “In a First, Caltech’s Space Solar Power Demonstrator Wirelessly Transmits Power in Space | www.caltech.edu.” Accessed: Nov. 14, 2023. [Online]. Available: https://www.caltech.edu/about/news/in-a-first-caltechs-space-solar-power-demonstrator-wirelessly-transmits-power-in-space

[3] “Space-Based Solar Power | Department of Energy.” Accessed: Nov. 14, 2023. [Online]. Available: https://www.energy.gov/space-based-solar-power

Cover Photo by Chindanai Charoenpanich on Unsplash

Solar Energy in Space